Wireless communication device for correcting offset between base station and wireless communication device and method of operating the same

ABSTRACT

A method of operating a wireless communication device for correcting an offset between a base station and the wireless communication device includes determining whether to perform offset correction using a first target synchronization signal block (SSB) to generate a determination result in response to changing a selected reception beam from a first reception beam to a second reception beam in an SSB period, the first target SSB being received via the second reception beam, and performing the offset correction on the second reception beam using at least one first neighbor SSB based on the determination result, the at least one first neighbor SSB being received via the first reception beam.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application Nos.10-2019-0025865 filed on Mar. 6, 2019, and 10-2019-0068810 filed on Jun.11, 2019, in the Korean Intellectual Property Office, the disclosures ofwhich are incorporated herein in their entirety by reference.

BACKGROUND

The inventive concepts relate to a wireless communication device forcorrecting an offset caused by a carrier frequency difference and/or atime synchronization error between the wireless communication device anda base station, and a method of operating the same.

As new radio access technology, recent 5th generation (5G) communicationsystems aim to provide data services at an ultrahigh speed of severalGbps using an ultra-wideband with a bandwidth of 100 MHz or more,compared to existing long term evolution (LTE) and LTE advanced (LTE-A)communication systems. However, since it is difficult to secure anultra-wideband frequency of 100 MHz or more in a frequency band ofseveral hundreds of MHz or several GHz used for LTE and LTE-A, 5Gcommunication systems consider a method of transmitting a signal using awide frequency band in a frequency band of 6 GHz or more. Specifically,it is considered to increase a transmission rate using a millimeter-waveband, such as a 28 GHz band or a 60 GHz band, in 5G communicationsystems. However, the size of a frequency band is proportional to thepath loss of the corresponding radio waves, and the path loss of radiowaves is considerable in an ultrahigh frequency, thus reducing a servicearea of 5G communication systems.

To overcome the reduction in the service area, beamforming, whichincreases the propagation range of radio waves by generating directionalbeams using a plurality of antennas, is considered as a significanttechnique in 5G communication systems. The beamforming technique may beapplied to each of a transmitter (e.g., a base station) and a receiver(e.g., a terminal), and may not only increase the service area but alsoreduce interference due to physical beam concentration in a targetdirection.

Since the effect of the beamforming technique is enhanced only when thedirection of a transmission beam of a transmitter is tuned to thedirection of a reception beam of a receiver in 5G communication systems,a technique of selecting an optimal or desirable transmission beamand/or an optimal or desirable reception beam would be advantageous.

SUMMARY

The inventive concepts provide a wireless communication device forincreasing communication performance by continuously performing offsetcorrection while selecting a reception beam optimally or desirably tunedto a certain base station in a wireless communication system and amethod of operating the wireless communication device.

According to an aspect of the inventive concepts, there is provided amethod of operating a wireless communication device for correcting anoffset between a base station and the wireless communication deviceincluding determining whether to perform offset correction using a firsttarget synchronization signal block (SSB) to generate a determinationresult in response to changing a selected reception beam from a firstreception beam to a second reception beam in an SSB period, the firsttarget SSB being received via the second reception beam, and performingthe offset correction on the second reception beam using at least onefirst neighbor SSB based on the determination result, the at least onefirst neighbor SSB being received via the first reception beam.

According to an aspect of the inventive concepts, there is provided amethod of operating a wireless communication device which communicateswith a base station via a selected beam pair including a selectedtransmission beam and a selected reception beam including receiving aplurality of neighbor synchronization signal blocks (SSBs) from the basestation via the selected reception beam, the plurality of neighbor SSBsbeing transmitted via a subset of a plurality of transmission beams, thesubset of the plurality of transmission beams not including the selectedtransmission beam, the selected reception beam being a first receptionbeam among a plurality of reception beams, and the selected transmissionbeam being a first transmission beam among the plurality of transmissionbeams, receiving a target SSB via a second reception beam among theplurality of reception beams in response to changing the selectedreception beam from the first reception beam to the second receptionbeam, the target SSB being transmitted via the first transmission beam,and performing at least one of automatic frequency control or symboltiming recovery on the second reception beam using the plurality ofneighbor SSBs.

According to an aspect of the inventive concepts, there is provided awireless communication device including a plurality of antennasconfigured to receive a radio frequency (RF) signal from a base stationvia a plurality of reception beams, a local oscillator configured togenerate an oscillation signal having a local oscillation frequency, andprocessing circuitry configured to generate a baseband signal using theRF signal and the oscillation signal, the baseband signal including atarget synchronization signal block (SSB) received via a first receptionbeam among the plurality of reception beams and at least one neighborSSB received via a second reception beam among the plurality ofreception beams in response to a selected reception beam changing fromthe first reception beam to the second reception beam, and determinewhether to perform an automatic frequency control on the localoscillation frequency using the at least one neighbor SSB based on adetermination result.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the inventive concepts will be more clearly understoodfrom the following detailed description taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a diagram of a wireless communication system according to anexample embodiment;

FIG. 2 is a diagram for explaining a synchronization signal includingsynchronization signal blocks (SSBs) received from a base station;

FIG. 3 is a block diagram of a wireless communication device accordingto an example embodiment;

FIG. 4 is a block diagram of an automatic frequency controller accordingto an example embodiment;

FIG. 5 is a diagram for explaining the operation of the automaticfrequency controller of FIG. 4;

FIGS. 6A and 6B are diagrams for explaining a method of determining aneighbor SSB, according to an example embodiment;

FIG. 7 is a flowchart of a method of operating an automatic frequencycontroller, according to an example embodiment;

FIG. 8 is a flowchart of a method of operating an automatic frequencycontroller, according to an example embodiment;

FIGS. 9A and 9B are flowcharts of a method of operating an automaticfrequency controller, according to example embodiments;

FIGS. 10A through 10C are diagrams for explaining a method of operatingan automatic frequency controller, according to an example embodiment;

FIG. 11 is a block diagram of a symbol timing recovery controlleraccording to an example embodiment;

FIG. 12 is a diagram for explaining the operation of the symbol timingrecovery controller of FIG. 11;

FIGS. 13A and 13B are diagrams for explaining a method of operating asymbol timing recovery controller, according to an example embodiment;and

FIG. 14 is a block diagram of an electronic apparatus according to anexample embodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments will be described in detail with reference tothe accompanying drawings.

FIG. 1 is a diagram of a wireless communication system 1 according to anexample embodiment, and FIG. 2 is a diagram for explaining asynchronization signal including synchronization signal blocks (SSBs)received from a base station.

Referring to FIG. 1, the wireless communication system 1 may include abase station 10 and/or a wireless communication device 100. Although itis illustrated in FIG. 1 that the wireless communication system 1includes only one base station 10 for convenience of description, it isjust an example embodiment, and the wireless communication system 1 mayinclude more base stations. The inventive concepts described below maybe applied to other base stations.

The wireless communication device 100 may access the wirelesscommunication system 1 by transmitting and/or receiving signals toand/or from the base station 10. The wireless communication system 1accessible by the wireless communication device 100 may be referred toas radio access technology (RAT). As a non-limiting example, thewireless communication system 1 may be a wireless communication system,such as a 5th generation (5G) communication system, a long termevolution (LTE) communication system, an LTE advanced (LTE-A)communication system, a code division multiple access (CDMA)communication system, and/or a global system for mobile (GSM)communication system, using a cellular network, a wireless local areanetwork (WLAN) communication system, and/or another wirelesscommunication system. Hereinafter, it is assumed that the wirelesscommunication system 1 accessed by the wireless communication device 100is a 5G communication system, but example embodiments are not limitedthereto, and it is apparent that the inventive concepts may be appliedto next generation wireless communication systems.

Wireless communication networks of the wireless communication system 1may support communication among a plurality of wireless communicationdevices including the wireless communication device 100 by sharingavailable network resources. For example, information may be transferredthrough wireless communication networks in various multiple access modessuch as a CDMA mode, a frequency division multiple access (FDMA) mode, atime division multiple access (TDMA) mode, an orthogonal FDMA (OFDMA)mode, a single carrier FDMA (SC-FDMA) mode, an OFDM-FDMA mode, anOFDM-TDMA mode, and/or an OFDM-CDMA mode.

The base station 10 may generally refer to a fixed station that maycommunicate with the wireless communication device 100 and/or anotherbase station, and may exchange data and/or control information with thewireless communication device 100 and/or another base station. Forexample, the base station 10 may be referred to as a node B, anevolved-node B (eNB), a next generation node B (gNB), a sector, a site,a base transceiver system (BTS), an access point (AP), a relay node, aremote radio head (RRH), a radio unit (RU), a cell, and/or a small cell.In this specification, a base station may be interpreted as referring orcorresponding to a partial area and/or function, which is covered by abase station controller (BSC) in CDMA, a node-B in wideband CDMA(WCDMA), and/or an eNB or a sector (or site) in LTE, in a comprehensivesense and may include various coverage regions, such as a mega cell, amacro cell, a micro cell, a pico cell, a femto cell, a relay node, anRRH, an RU, and/or a small-cell communication range.

The wireless communication device 100 may be stationary or mobile asuser equipment (UE) and may refer to a wireless communication devicethat may transmit and/or receive data and/or control information toand/or from a base station. For example, the wireless communicationdevice 100 may be referred to as a mobile station (MS), a mobileterminal (MT), a user terminal (UT), a subscriber station (SS), awireless device, a portable device, and/or a terminal.

Referring to FIG. 1, the wireless communication device 100 may beconnected to the base station 10 through a wireless channel and mayprovide various communication services. The base station 10 may serviceall or some user traffic through a shared channel, may gather stateinformation, such as a buffer state, an available transmission powerstate, and/or a channel state, and/or may perform scheduling. Thewireless communication system 1 may support beamforming using OFDM as awireless access technique. In addition, the wireless communicationsystem 1 may support an adaptive modulation and coding (AMC) scheme inwhich a modulation scheme and a channel coding rate may be determinedaccording to the channel state of the wireless communication device 100.

The wireless communication system 1 may transmit and/or receive signalsusing a wide frequency band in a frequency band of 6 GHz or more. Forexample, the wireless communication system 1 may increase a datatransmission rate using a millimeter-wave band such as a 28 GHz band ora 60 GHz band. Since signal attenuation per distance is relatively largein the millimeter-wave band, the wireless communication system 1 maysupport transmission and/or reception based on a directional beam, whichis generated using multiple antennas, to secure or improve coverage. Thewireless communication system 1 may perform beam sweeping for thetransmission and/or reception based on a directional beam.

Beam sweeping is a process in which the wireless communication device100 and the base station 10 may sequentially or randomly sweepdirectional beams having a certain pattern and may determine atransmission beam and a reception beam having directions that are intune with each other. The transmission beam and the reception beamhaving directions that are in tune with each other may be determined asa transmission/reception beam pair (may also be referred to as a “beampair’). At this time, the transmission beam and the reception beamselected as being in tune with each other as a result of the beamsweeping may be referred to as a best transmission beam (may also bereferred to as a “selected transmission beam”) and a best reception beam(may also be referred to as a “selected reception beam”), respectively(may collectively be referred to as a “selected beam pair”). A beampattern may be the shape of a beam, which is determined by the width anddirection of the beam. Hereinafter, it is assumed that, as a result ofthe beam sweeping, a first reception beam RX_B1 is determined as thebest reception beam among a plurality of first through p-th receptionbeams RX_B1 through RX_Bp (e.g., the first RX_B1, the second RX_B2, thethird RX_B3, . . . , the p-th RX_Bp) of the wireless communicationdevice 100 and a first transmission beam TX_B1 is determined as the besttransmission beam among a plurality of transmission beams TX_B1 throughTX_Bn (e.g., the first TX_B1, the second TX_B2, the third TX_B3, thefourth TX_B4, the fifth TX_B5, the sixth TX_B6, the seventh TX_B7, theeighth TX_B8, . . . , the n-th TX_Bn) of the base station 10.Afterwards, the wireless communication device 100 may sweep otherreception beams than the first reception beam RX_B1 to select a new bestreception beam (also referred to herein as “changing” from a firstreception beam to a second reception beam) according to a variablecommunication environment of the wireless communication device 100(e.g., a change in a communication environment due to a movement of thewireless communication device 100) and may periodically receive aplurality of SSBs transmitted from the base station 10 via thetransmission beams TX_B1 through TX_Bn.

Referring to FIGS. 1 and 2, the base station 10 may transmit a signalincluding one of first through n-th SSBs SSB1 through SSBn (e.g., thefirst SSB SSB1, the second SSB SSB2, the third SSB SSB3, the fourth SSBSSB4, the fifth SSB SSB5, the sixth SSB SSB6, . . . , the n-th SSB SSBn)to the wireless communication device 100 via one of the transmissionbeams TX_B1 through TX_Bn. For example, the base station 10 may transmita signal including the first SSB SSB1 to the wireless communicationdevice 100 via the first transmission beam TX_B1 and transmit a signalincluding the second SSB SSB2 to the wireless communication device 100via the second transmission beam TX_B2. In this manner, the base station10 may transmit various SSBs, e.g., SSB1 through SSBn, to the wirelesscommunication device 100 via the transmission beams TX_B1 through TX_Bn,and the wireless communication device 100 may continuously perform anoperation of updating a best reception beam (e.g., a selected receptionbeam), which is optimally or desirably tuned to a best transmission beam(e.g., a selected transmission beam), using the first through n-th SSBsSSB1 through SSBn.

Referring to FIG. 2, an SSB may include a primary synchronization signal(PSS), a secondary synchronization signal (SSS), and/or a physicalbroadcast channel (PBCH). For example, an SSB may include four symbols,and each of a PSS, an SSS, and a PBCH may be located at a positioncorresponding to certain resource blocks (RBs) in a frequency-axisdirection. In addition, an RB may include 12 consecutive subcarriers.For example, a PSS corresponding to a first symbol may be transmitted tothe wireless communication device 100 through 127 subcarriers.

For example, two SSBs may be allocated to a slot of a signal, and thewireless communication device 100 may receive an SSB burst set from thebase station 10 during a certain SSB period. For example, assuming thatthe wireless communication system 1 is a new radio (NR) system using asubcarrier spacing of 15 kHz, the wireless communication device 100 mayreceive an SSB burst set including “n” SSBs, e.g., SSB1 through SSBn,from the base station 10 during an SSB period. At this time, the lengthof a single slot may be 1 ms and the SSB period may be 20 ms. However,this is just an example embodiment, and embodiments are not limitedthereto. The number of SSBs in the SSB burst set, the SSB period, and/orthe length of a single slot may vary with the size of a subcarrierspacing, the period of a synchronization signal set in the base station10, and/or the like.

The wireless communication device 100 may receive the first through n-thSSBs SSB1 through SSBn from the base station 10. Hereinafter, an SSBtransmitted from the base station 10 via the best transmission beam isdefined as a target SSB. For example, when the best transmission beam isthe first transmission beam TX_B1, the target SSB may be the first SSBSSB1.

According to an example embodiment, the wireless communication device100 may continuously perform an operation of correcting an offset causedby a carrier frequency difference and/or a time synchronization errorbetween the wireless communication device 100 and the base station 10while performing sweeping to update the best reception beam. In anembodiment, the operation of correcting an offset may include anautomatic frequency control for correcting a frequency offset betweenthe base station 10 and the wireless communication device 100 and/or asymbol timing recovery for correcting a symbol timing offset between thebase station 10 and the wireless communication device 100.

The operation of the wireless communication device 100 according to anexample embodiment will be described assuming that the best transmissionbeam is the first transmission beam TX_B1 and the best reception beam isthe first reception beam RX_B1, as described above.

The wireless communication device 100 may change the first receptionbeam RX_B1 to the second reception beam RX_B2 at a point within acertain SSB period (e.g., a random, set or determined point) to updatethe best reception beam and may determine whether to perform offsetcorrection on the second reception beam RX_B2 using the target SSB,e.g., the first SSB SSB1, received via the second reception beam RX_B2.In other words, the wireless communication device 100 may perform offsetcorrection on the first reception beam RX_B1 using SSBs received via thefirst reception beam RX_B1 within the certain SSB period and, when thefirst reception beam RX_B1 is changed to the second reception beam RX_B2(e.g., when the selected reception beam is changed from the firstreception beam RX_B1 to the second reception beam RX_B2), the wirelesscommunication device 100 may determine whether to perform offsetcorrection on the second reception beam RX_B2 using the target SSB,e.g., the first SSB SSB1, received via the second reception beam RX_B2.Hereinafter, offset correction on a specific reception beam may beinterpreted as offset correction performed based on a signal receivedvia the specific reception beam.

The wireless communication device 100 may perform offset correction onthe second reception beam RX_B2 selectively using one of a target SSBand/or a neighbor SSB based on the determination result. The neighborSSB may be used instead of the target SSB for offset correction and maybe an SSB that is received via the best reception beam (e.g., the firstreception beam RX_B1) before sweeping. A method of determining aneighbor SSB will be described in detail with reference to FIGS. 6A and6B below.

According to embodiments, even at the time when the first reception beamRX_B1 is changed to the second reception beam RX_B2, the wirelesscommunication device 100 may continuously (e.g., repeatedly) performoffset correction on the second reception beam RX_B2, following theoffset correction on the first reception beam RX_B1.

According to an example embodiment, the wireless communication device100 may generate (or measure, or determine) a reception quality withrespect to the target SSB, e.g., the first SSB SSB1, compare thereception quality with a reference quality, and determine to performoffset correction on the second reception beam RX_B2 using the targetSSB, e.g., the first SSB SSB1, when the reception quality is equal to orhigher than the reference quality. When the reception quality for thetarget SSB, e.g., the first SSB SSB1, is lower than the referencequality, the wireless communication device 100 may determine to performoffset correction on the second reception beam RX_B2 using at least oneneighbor SSB. In other words, when the reception quality for the targetSSB, e.g., the first SSB SSB1, received via the second reception beamRX_B2 is not satisfactory, the wireless communication device 100 mayperform offset correction on the second reception beam RX_B2 using atleast one neighbor SSB instead of the target SSB, e.g., the first SSBSSB1. In addition, the reception quality of an SSB may include at leastone selected from a reference signal received power (RSRP) of the SSBand/or a signal-to-noise ratio (SNR) of the SSB. According to someexample embodiments, the RSRP and/or the SNR of each SSB may bedetermined using structures and/or methods known to a person havingordinary skill in the art. However, this is just an example embodiment,and embodiments are not limited thereto. The wireless communicationdevice 100 may generate the reception quality of an SSB based on variousmatrices that may indicate the reception quality.

According to an example embodiment, the wireless communication device100 may continuously perform offset correction selectively using one ofa target SSB and/or a neighbor SSB even while operating to update thebest reception beam that is in optimal or desired tune with the besttransmission beam, thereby increasing communication performance.

FIG. 3 is a block diagram of the wireless communication device 100according to an example embodiment.

Referring to FIG. 3, the wireless communication device 100 may include aplurality of antennas 110, a radio frequency (RF) circuit 120, aprocessor 130, a local oscillator 140, and/or a memory 150. According toan example embodiment, the processor 130 may include an automaticfrequency controller 131, a symbol timing recovery controller 132,and/or a sampler 133. Although not shown, the processor 130 may furtherinclude another element, e.g., an analog-to-digital converter. Accordingto some example embodiments, operations described herein as beingperformed by the base station 10, the wireless communication device 100,the RF circuit 120, the processor 130, the local oscillator 140, theautomatic frequency controller 131, the symbol timing recoverycontroller 132, and/or the sampler 133 may be performed by processingcircuitry. The term ‘processing circuitry,’ as used in the presentdisclosure, may refer to, for example, hardware including logiccircuits; a hardware/software combination such as a processor executingsoftware; or a combination thereof. For example, the processingcircuitry more specifically may include, but is not limited to, acentral processing unit (CPU), an arithmetic logic unit (ALU), a digitalsignal processor, a microcomputer, a field programmable gate array(FPGA), a System-on-Chip (SoC), a programmable logic unit, amicroprocessor, application-specific integrated circuit (ASIC), etc. Forexample, each of the elements in the wireless communication device 100(e.g., the RF circuit 120, the processor 130, and/or the localoscillator 140) may be implemented as a hardware block including ananalog circuit and/or a digital circuit or a software block including aplurality of instructions executed by at least one processor and/or thelike. In some embodiments, the automatic frequency controller 131 and/orthe symbol timing recovery controller 132 may be implemented in a modemchip.

The wireless communication device 100 may receive a signal from a basestation through a downlink channel. The characteristics of the downlinkchannel may be changed by the states and/or circumstances of thewireless communication device 100 and/or the base station. In otherwords, an offset between the wireless communication device 100 and thebase station may occur with respect to communication parameters due to acarrier frequency difference and/or a time synchronization errortherebetween. The wireless communication device 100 may perform anoperation of correcting such an offset to increase or improvecommunication performance.

The RF circuit 120 may receive an input signal IN from a base stationthrough the antennas 110 and receive an oscillation signal OS from thelocal oscillator 140. The RF circuit 120 may generate a baseband signalBS from the input signal IN and the oscillation signal OS and output thebaseband signal BS to the processor 130. Here, the input signal IN maybe an RF signal that has a high central frequency due to a carrier (orcorresponding to a carrier frequency), and the oscillation signal OS mayhave a local oscillation frequency corresponding to the carrier (e.g.,corresponding to the carrier frequency). For example, the RF circuit 120may include an analog down-conversion mixer and may generate thebaseband signal BS by down-converting the frequency of the input signalIN. When the local oscillation frequency does not coincide with thecarrier frequency of the input signal IN, a frequency offset may occur.

According to an example embodiment, the automatic frequency controller131 may correct a frequency offset between the base station 10 and thewireless communication device 100 selectively using one of a target SSBand/or a neighbor SSB during an operation of updating the best receptionbeam. In some embodiments, the target SSB and the neighbor SSB may bereceived in one SSB period. In detail, when a first reception beam ischanged to a second reception beam as a result of updating the bestreception beam, the automatic frequency controller 131 may select one ofa target SSB and/or a neighbor SSB and generate (or estimate) afrequency offset with respect to the input signal IN received via thesecond reception beam. The automatic frequency controller 131 maygenerate a frequency control signal F_CTR, which makes the localoscillation frequency of the oscillation signal OS coincide with thecarrier frequency of the input signal IN, based on the frequency offset.Specific embodiments of the automatic frequency controller 131 will bedescribed with reference to FIGS. 4 through 10C below.

A symbol timing offset may occur when symbol timing for data sampling ina base station does not coincide with symbol timing for data sampling inthe wireless communication device 100.

According to an example embodiment, the symbol timing recoverycontroller 132 may correct a symbol timing offset between the basestation 10 and the wireless communication device 100 selectively usingone of a target SSB and/or a neighbor SSB during an operation ofupdating the best reception beam. In detail, when a first reception beamis changed to a second reception beam as a result of updating the bestreception beam, the symbol timing recovery controller 132 may select onefrom a target SSB and/or a neighbor SSB and generate (or estimate) asymbol timing offset with respect to the input signal IN received viathe second reception beam. The symbol timing recovery controller 132 maygenerate a symbol timing recovery control signal STR_CTR, which makesthe symbol timing of the base station 10 coincide with the symbol timingof the wireless communication device 100, based on the symbol timingoffset, and may output the symbol timing recovery control signal STR_CTRto the sampler 133. Specific embodiments of the symbol timing recoverycontroller 132 will be described with reference to FIGS. 12 through 13Bbelow.

The memory 150 may store data that may be used when the automaticfrequency controller 131 and the symbol timing recovery controller 132perform operations according to example embodiments. According to someexample embodiments, the memory 150 may be implemented using a RandomAccess Memory (RAM), a flash memory, a Read Only Memory (ROM), anElectrically Programmable ROM (EPROM), an Electrically ErasableProgrammable ROM (EEPROM), registers, a hard disk, a removable disk, aCD ROM, and/or any other form of storage medium known in the art.

FIG. 4 is a block diagram of the automatic frequency controller 131according to an example embodiment and FIG. 5 is a diagram forexplaining the operation of the automatic frequency controller 131 ofFIG. 4.

Referring to FIG. 4, the automatic frequency controller 131 may includea neighbor SSB determinator 131 a and/or an alternate frequency offsetgenerator 131 b. The neighbor SSB determinator 131 a may determine atleast one neighbor SSB, which may be used instead of the target SSB toperform frequency offset correction, from a plurality of SSBs receivedwithin a certain SSB period. A specific embodiment of the neighbor SSBdeterminator 131 a will be described with reference to FIGS. 6A and 6Bbelow. According to some example embodiments, operations describedherein as being performed by the neighbor SSB determinator 131 a and/orthe alternate frequency offset generator 131 b may be performed byprocessing circuitry.

The alternate frequency offset generator 131 b may generate an alternatefrequency offset using the neighbor SSB determined by the neighbor SSBdeterminator 131 a. The automatic frequency controller 131 may performautomatic frequency control based on the alternate frequency offset.Specific embodiments of the alternate frequency offset generator 131 bwill be described with reference to FIGS. 8 through 10C below.

Although the operations of the neighbor SSB determinator 131 a and thealternate frequency offset generator 131 b have been separatelydescribed with reference to FIG. 4 for convenience of description, theoperations may be defined as being performed by the automatic frequencycontroller 131.

In FIG. 5, it is assumed that a j-th SSB SSB_j,m is a target SSB, ani-th SSB SSB_i,m and a k-th SSB SSB_k,m are neighbor SSBs, the bestreception beam is a first reception beam, and a reception beam to whichthe best reception beam is changed via a sweeping reception beam is asecond reception beam. The horizontal direction in FIG. 5 does notindicate a time axis. In addition, the illustration in FIG. 5 is just anexample, and embodiments are not limited thereto.

Referring to FIG. 5, a wireless communication device may receive aplurality of x-th through y-th SSBs SSB_x,m through SSB_y,m from a basestation in an m-th SSB period, where “m” is an integer. In detail, thewireless communication device may receive neighbor SSBs, e.g., the x-thSSB SSB_x,m and the y-th SSB SSB_y,m via the first reception beam andmay receive the target SSB, e.g., the j-th SSB SSB_j,m, via the secondreception beam. The automatic frequency controller 131 may continuouslyperform automatic frequency control on the first reception beam based ona frequency offset that is generated using a target SSB received in anSSB period before the m-th SSB period. However, as the first receptionbeam is changed to the second reception beam (e.g., the best receptionbeam, initially selected as the first reception beam, is changed,updated and/or re-selected to the second reception beam) in the m-th SSBperiod, it may be desirable to determine whether the target SSB, e.g.,the j-th SSB SSB_j,m, received via the second reception beam is suitablefor a first automatic frequency control AFC1.

Accordingly, the automatic frequency controller 131 may determinewhether to perform the first automatic frequency control AFC1 on thesecond reception beam using the target SSB, e.g., the j-th SSB SSB_j,m,when the first reception beam is changed to the second reception beam toupdate the best reception beam (e.g., in response to the selectedreception beam changing from the first reception beam to the secondreception beam) in the m-th SSB period. The automatic frequencycontroller 131 may generate or determine a reception quality of thetarget SSB, e.g., the j-th SSB SSB_j,m, and determine whether to performthe first automatic frequency control AFC1 based on the receptionquality. For example, the automatic frequency controller 131 may performthe first automatic frequency control AFC1 using the target SSB, e.g.,the j-th SSB SSB_j,m, when the reception quality of the target SSB,e.g., the j-th SSB SSB_j,m, is equal to or higher than a referencequality. The automatic frequency controller 131 may generate channelestimates using at least one selected from a PSS, an SSS, and/or a PBCHof the target SSB, e.g., the j-th SSB SSB_j,m, and generate adifferential correlation result by calculating a differentialcorrelation of the channel estimates. Since a frequency offset exertsnearly the same or a similar influence on all subcarriers throughout thewhole bandwidth, the automatic frequency controller 131 may calculate adifferential correlation by multiplying a channel estimate of a currenttime index by a complex conjugate of a channel estimate of a previoustime index and accumulating multiplication results. In addition, theautomatic frequency controller 131 may calculate a phase estimate fromthe differential correlation result. Here, the phase estimate may referto an estimated value of a phase change, and the phase change may beproportional to a frequency offset between a carrier frequency and alocal oscillation frequency. In detail, a frequency offset Δf may becalculated using Equation 1:

$\begin{matrix}{{\Delta\; f} = {\frac{N}{2{\pi\left( {N + {CP}} \right)}\delta\; T}{\angle\left( {\sum\limits_{k = 0}^{N_{s} - 1}\;{{Y_{m + 1}\lbrack k\rbrack}{Y_{m}^{*}\lbrack k\rbrack}}} \right)}}} & (1)\end{matrix}$

Ym[k] may be a result of estimating a frequency-domain channel in aresource element, which corresponds to an index of a k-th referencesignal in an m-th symbol. δT may be a distance between two symbols (forexample, when the product of an (m=L)-th symbol and an (m=L+2)-th symbolis calculated, δT may be 2), and Ns may be the number of availablereference signals. N may be a Fast Fourier Transform (FFT) size, and CPmay be the length of a cyclic prefix.

The automatic frequency controller 131 may generate a frequency offsetusing the target SSB, e.g., the j-th SSB SSB_j,m, based on Equation 1and perform the first automatic frequency control AFC1 based on thefrequency offset.

The automatic frequency controller 131 may perform a second automaticfrequency control AFC2 and/or a third automatic frequency control AFC3using the neighbor SSBs, e.g., the i-th SSB SSB_i,m and/or the k-th SSBSSB_k,m, when the reception quality of the target SSB, e.g., the j-thSSB SSB_j,m, is lower than the reference quality. In some embodiments,the automatic frequency controller 131 may select one of the i-th SSBSSB_i,m and the k-th SSB SSB_k,m and perform an automatic frequencycontrol corresponding to the selected neighbor SSB using the selectedneighbor SSB. The automatic frequency controller 131 may generate analternate frequency offset using the neighbor SSBs, e.g., the i-th SSBSSB_i,m and/or the k-th SSB SSB_k,m, based on Equation 1. Thereafter,the automatic frequency controller 131 may perform the second and/orthird automatic frequency controls AFC2 and/or AFC3 based on thealternate frequency offset.

Specific embodiments of the second and third automatic frequencycontrols AFC2 and AFC3 respectively using the neighbor SSBs, e.g., thei-th SSB SSB_i,m and the k-th SSB SSB_k,m, will be described withreference to FIGS. 8 through 10C below.

FIGS. 6A and 6B are diagrams for explaining a method of determining aneighbor SSB, according to an example embodiment. FIG. 3 will also bereferred to in the description below.

Referring to FIGS. 3 and 6A, the processor 130 may generate a receptionquality (e.g., an SNR and/or RSRP) of each of the first through n-thSSBs SSB1 through SSBn, which are received in at least one SSB periodbefore the m-th SSB period of FIG. 5, or a plurality of SSB periodsincluding the m-th SSB periods, with respect to the first through p-threception beams RX_B1 through RX_Bp. For example, the processor 130 maygenerate the SNR or RSRP of the n-th SSB SSBn when the n-th SSB SSBn isreceived via each of the first through p-th reception beams RX_B1through RX_Bp. An n-th table TB_SSBn may include information aboutreception quality of the n-th SSB SSBn with respect to the first throughp-th reception beams RX_B1 through RX_Bp. In this manner, each of firstthrough (n−1)-th tables TB_SSB1 through TB_SSBn−1 may includeinformation about reception quality of a corresponding one of the firstthrough (n−1)-th SSBs SSB1 through SSBn−1 with respect to the firstthrough p-th reception beams RX_B1 through RX_Bp. The first through n-thtables TB_SSB1 through TB_SSBn may be stored in the memory 150, and theprocessor 130 may access the memory 150 to refer to the first throughn-th tables TB_SSB1 through TB_SSBn.

Referring to FIG. 6B, the automatic frequency controller 131 may obtaina reception quality of the h-th SSB SSBh (where “h” is an integer lessthan “n”), which is received via the best reception beam, with referenceto the first through n-th tables TB_SSB1 through TB_SSBn of FIG. 6A inoperation S100. For example, when the best reception beam is the firstreception beam RX_B1, the automatic frequency controller 131 may obtainthe reception quality of the h-th SSB SSBh corresponding to the firstreception beam RX_B1 with reference to the h-th table TB_SSBh. Accordingto some example embodiments, prior to operation S100 in a firstiteration, the h may be initialized to have a value of ‘1’. Theautomatic frequency controller 131 may determine whether the receptionquality is equal to or higher than a reference quality in operationS110. The reference quality may be set using various methods todetermine a neighbor SSB. For example, the reference quality may be setbased on the reception quality of a target SSB received via the bestreception beam.

When the answer is “YES” in operation S110, the h-th SSB SSBh may bedetermined as the neighbor SSB in operation S120. When the answer is“NO” in operation S110, or after operation S120, the automatic frequencycontroller 131 may determine whether “h” is equal to “n” in operationS130. When the answer is “NO” in operation S130, “h” is counted up(e.g., incremented) in operation S140, and the method proceeds tooperation S100. When the answer is “YES”, the automatic frequencycontroller 131 may perform an automatic frequency control selectivelyusing at least one neighbor SSB.

FIG. 7 is a flowchart of a method of operating an automatic frequencycontroller, according to an example embodiment. FIG. 3 will also bereferred to in the description below.

Referring to FIGS. 3 and 7, the automatic frequency controller 131 maychange the best reception beam formed in the antennas 110 to a receptionbeam having a different pattern in operation S200. For example, theautomatic frequency controller 131 may change the best reception beamformed in the antennas 110 from a first reception beam to a secondreception beam to update the best reception beam. The automaticfrequency controller 131 may determine whether to perform automaticfrequency control on the second reception beam using a target SSB, whichis received via the second reception beam, in operation S210. In anexample embodiment, the automatic frequency controller 131 may performthe determination based on whether the reception quality of the targetSSB received via the second reception beam is equal to or higher than areference quality. The reference quality may be set using variousmethods to determine whether to perform the automatic frequency controlusing the target SSB.

In an example embodiment, the reference quality may be set based on thereception quality of at least one neighbor SSB in the same SSB period,or a similar SSB period, as the target SSB is received and/or thereception quality of a target SSB received in at least one other SSBperiod. Referring to FIG. 5 for description in detail, the referencequality may be set based on the reception quality of the neighbor SSBs,e.g., the i-th SSB SSB_i,m and the k-th SSB SSB_k,m, in the m-th SSBperiod, in which the target SSB, e.g., the j-th SSB SSB_j,m, isreceived, and the reception quality of a target SSB received in at leastone other SSB period (e.g., an (m−1)-th SSB period) before the m-th SSBperiod. However, this is just an example embodiment, and embodiments arenot limited thereto. The reference quality may be set based on variousmatrices such that whether a frequency offset error caused by using atarget SSB received via a changed reception beam is within a tolerancelimit.

When the answer is “YES” in operation S210, that is, when the receptionquality of the target SSB is equal to or higher than the referencequality, the automatic frequency controller 131 may perform theautomatic frequency control using the target SSB in operation S220.Otherwise, when the answer is “NO” in operation S210, that is, when thereception quality of the target SSB is lower than the reference quality,the automatic frequency controller 131 may perform the automaticfrequency control using at least one neighbor SSB in operation S230.

FIG. 8 is a flowchart of a method of operating an automatic frequencycontroller, according to an example embodiment. FIG. 3 will also bereferred to in the description below.

Referring to FIGS. 3 and 8, when it is determined that the automaticfrequency control is performed using at least one neighbor SSB afteroperation S210 in FIG. 7, the automatic frequency controller 131 mayobtain a reception quality corresponding to the at least one neighborSSB in operation S231. For example, the automatic frequency controller131 may generate (or measure or determine) the reception quality of theneighbor SSB received via the best reception beam. The automaticfrequency controller 131 may determine suitability of an automaticfrequency control with respect to the neighbor SSB in operation S233. Inother words, the automatic frequency controller 131 may determinewhether it is suitable to perform the automatic frequency control usingthe neighbor SSB. In an example embodiment, the automatic frequencycontroller 131 may determine whether the reception quality of theneighbor SSB is equal to or higher than a reference quality (e.g., aneighbor SSB having a reception quality equal to or higher than thereference quality may be determined to be suitable for use in performingthe automatic frequency control). The reference quality may be set usingvarious methods to determine the suitability of an automatic frequencycontrol with respect to the neighbor SSB. In an example embodiment, thereference quality may be set based on a reception quality of at leastone neighbor SSB received via the best reception beam in other SSBperiods.

When the answer is “YES” in operation S233, that is, when the receptionquality of the neighbor SSB is equal to or higher than the referencequality, the automatic frequency controller 131 may perform theautomatic frequency control based on alternate frequency offsetsgenerated (or estimated) using the neighbor SSB in operation S235.Otherwise, when the answer is “NO” in operation S233, that is, when thereception quality of the neighbor SSB is lower than the referencequality, the automatic frequency controller 131 may skip the automaticfrequency control with respect to a reception beam changed from the bestreception beam in operation S237.

FIGS. 9A and 9B are flowcharts of a method of operating an automaticfrequency controller, according to example embodiments. FIG. 3 will alsobe referred to in the description below.

Referring to FIGS. 3 and 9A, when there are a plurality of neighborSSBs, the automatic frequency controller 131 may select an SSB to beused for the automatic frequency control from among the neighbor SSBs inoperation S235_1 a after operation S233 in FIG. 8. In an exampleembodiment, the automatic frequency controller 131 may select a neighborSSB having a highest reception quality among the neighbor SSBs. Theautomatic frequency controller 131 may perform the automatic frequencycontrol based on an alternate frequency offset corresponding to theselected SSB in operation S235_2 a.

Referring to FIG. 9B, when there are a plurality of neighbor SSBs, theautomatic frequency controller 131 may calculate an average of alternatefrequency offsets corresponding to the neighbor SSBs (to obtain orgenerate a calculated average alternate frequency offset) in operationS235_1 b after operation S233 in FIG. 8. The automatic frequencycontroller 131 may perform the automatic frequency control based on thecalculated average alternate frequency offset in operation S235_2 b.

FIGS. 10A through 10C are diagrams for explaining a method of operatingan automatic frequency controller, according to an example embodiment.FIG. 3 will also be referred to in the description below.

Referring to FIGS. 10A and 10B, a frequency offset between atransmission frequency freq_TX (or a carrier frequency) of a basestation and a local oscillation frequency of the wireless communicationdevice 100 may be different for each SSB (each of the plurality of x-ththrough y-th SSBs SSB_x,m−1 through SSB_y,m−1). For example, thewireless communication device 100 may receive a target SSB, e.g., a j-thSSB SSB_j,m−1, and neighbor SSBs, e.g., an i-th SSB SSB_i,m−1 and a k-thSSB SSB_k,m−1, from a base station via the best reception beam (e.g., afirst reception beam) in the (m−1)-th SSB period before the m-th SSBperiod; and a frequency offset Δfreq_SSBj,m−1 generated (or estimated)using the target SSB, e.g., the j-th SSB SSB_j,m−1, may be differentfrom frequency offsets Δfreq_SSBi,m−1 and Δfreq_SSBk,m−1 generated (orestimated) using the neighbor SSBs, e.g., the i-th SSB SSB_i,m−1 and thek-th SSB SSB_k,m−1. For example, an i-th offset difference diff_freq_imay be between the frequency offset Δfreq_SSBj,m−1 generated (orestimated) using the target SSB, e.g., the j-th SSB SSB_j,m−1, and thefrequency offset Δfreq_SSBi,m−1 generated (or estimated) using the i-thSSB SSB_i,m−1; and a k-th offset difference diff_freq_k may be betweenthe frequency offset Δfreq_SSBj,m−1 generated (or estimated) using thetarget SSB, e.g., the j-th SSB SSB_j,m−1, and the frequency offsetΔfreq_SSBk,m−1 generated (or estimated) using the k-th SSB SSB_k,m−1.

The automatic frequency controller 131 may generate the i-th and k-thoffset differences diff_freq_i and diff_freq_k using the frequencyoffsets Δfreq_SSBj,m−1, Δfreq_SSBi,m−1, and Δfreq_SSBk,m−1, which aregenerated while performing the first through third automatic frequencycontrols AFC1 through AFC3.

According to an example embodiment, the automatic frequency controller131 may generate an offset difference between a frequency offset, whichis generated (or estimated) using a target SSB received via the bestreception beam in a certain SSB period, and each of frequency offsets,which are respectively generated (or estimated) using neighbor SSBsreceived via the best reception beam. The automatic frequency controller131 may reflect the offset differences in an automatic frequency controlusing at least one SSB selected from neighbor SSBs afterwards. Indetail, the automatic frequency controller 131 may use the i-th and k-thoffset differences diff_offset_i and diff_offset_k when generating (orestimating) alternate frequency offsets using neighbor SSBs, e.g., thei-th SSB SSB_i,m and the k-th SSB SSB_k,m, received in the m-th SSBperiod in FIG. 5.

Referring to FIG. 10C, after operation S233 in FIG. 8, the automaticfrequency controller 131 may generate offset differences correspondingto neighbor SSBs in operation S235_1 c. For example, the automaticfrequency controller 131 may generate the offset differences fromfrequency offsets, which are generated (or estimated) using the targetSSB received via the best reception beam and the neighbor SSBs in acertain SSB period. The automatic frequency controller 131 may generatean alternate frequency offset by applying the offset differences to thefrequency offsets corresponding to the neighbor SSBs in operation S235_2c. In detail, the automatic frequency controller 131 may apply theoffset differences using Equation 2:

$\begin{matrix}{{\Delta\;{f_{AFC}\left( {\Delta\; f_{Alternate}} \right)}}{{{where}\mspace{14mu}\Delta\; f_{Alternate}} = {{\Delta\; f_{{SSB}_{{- j},{m - 1}}}} + {\frac{1}{\Sigma_{y \in {{Neighbor}\mspace{14mu}{SSBs}}}\mspace{14mu}\sigma_{e{(y)}}^{- 2}}\Sigma_{x \in {{Neighbor}\mspace{14mu}{SSBs}}}\frac{e(x)}{\sigma_{e{(x)}}^{- 2}}}}}{{e(x)} = {{\Delta\; f_{{SSB}_{{- x},m}}} - {\Delta\; f_{{SSB}_{{- x},{m - 1}}}}}}} & (2)\end{matrix}$

In some embodiments, when the quality of Δf_(SSB) _(_x,m) −Δf_(SSB)_(_x,m−1)

is not known, a simple arithmetic mean may be calculated using Equation3:

$\begin{matrix}{{\Delta\; f_{Alternate}} = {{\Delta\; f_{{SSB}_{{- j},{m - 1}}}} + {\frac{1}{{{Neighbor}\mspace{14mu}{SSBs}}}{\sum\limits_{x \in {{Neighbor}\mspace{14mu}{SSBs}}}{e(x)}}}}} & (3)\end{matrix}$

When there are a plurality of neighbor SSBs SSB_x, the automaticfrequency controller 131 may generate an alternate frequency offsetΔf_(Alternate) by performing a calculation on a frequency offsetΔf_(SSP_j,m−1) corresponding to the target SSB, e.g., the j-th SSBSSB_j,m−1, and a frequency offset Δf_(SSB_x,m−1) corresponding to aneighbor SSB, e.g., the x-th SSB SSB_x,m−1, in the (m−1)-th SSB period(or a random SSB period) and a frequency offset Δf_(SSB_x,m)corresponding to the neighbor SSB, e.g., the x-th SSB SSB_x,m, in them-th SSB period, based on Equation 2 or 3. The automatic frequencycontroller 131 may perform an automatic frequency control based on anapplication result (e.g., the alternate frequency offset Δf_(Alternate))in operation S235_3 c.

FIG. 11 is a block diagram of the symbol timing recovery controller 132according to an example embodiment. FIG. 12 is a diagram for explainingthe operation of the symbol timing recovery controller 132 of FIG. 11.

Referring to FIG. 11, the symbol timing recovery controller 132 mayinclude a neighbor SSB determinator 132 a and/or an alternate symboltiming offset generator 132 b. The neighbor SSB determinator 132 a maydetermine at least one neighbor SSB, which may be used instead of atarget SSB to perform symbol timing recovery, from a plurality of SSBsreceived within a certain SSB period. The method of determining aneighbor SSB discussed in association with FIGS. 6A and 6B performed bythe neighbor SSB determinator 131 a of FIG. 4 may also be performed bythe neighbor SSB determinator 132 a, and therefore, detaileddescriptions thereof will be omitted. According to some exampleembodiments, operations described herein as being performed by theneighbor SSB determinator 132 a and/or the alternate symbol timingoffset generator 132 b may be performed by processing circuitry.

The alternate symbol timing offset generator 132 b may generate analternate symbol timing offset using the neighbor SSB determined by theneighbor SSB determinator 132 a. The symbol timing recovery controller132 may perform symbol timing recovery based on the alternate symboltiming offset. The methods of operating the automatic frequencycontroller 131 discussed in association with FIGS. 7-9B may beidentically or similarly applied to the symbol timing recoverycontroller 132. In other words, similarly to the automatic frequencycontroller 131, the symbol timing recovery controller 132 may select oneof a target SSB and/or at least one neighbor SSB, which are received inan SSB period corresponding to a time when the best reception beam ischanged to another reception beam as a result of updating the bestreception beam, and may perform symbol timing recovery with respect tothe changed reception beam.

In FIG. 12, it is assumed that the j-th SSB SSB_j,m is a target SSB, thei-th SSB SSB_i,m and the k-th SSB SSB_k,m are neighbor SSBs, the bestreception beam is a first reception beam, and a reception beam to whichthe best reception beam is changed via a sweeping reception beam is asecond reception beam. The horizontal direction in FIG. 12 does notindicate a time axis. In addition, the illustration of FIG. 12 is justan example, and embodiments are not limited thereto.

Referring to FIG. 12, a wireless communication device may receive theplurality of x-th through y-th SSBs SSB_x,m through SSB_y,m from a basestation in an m-th SSB period, where “m” is an integer. In detail, thewireless communication device may receive neighbor SSBs, e.g., the x-thSSB SSB_x,m and the y-th SSB SSB_y,m via the first reception beam andmay receive the target SSB, e.g., the j-th SSB SSB_j,m, via the secondreception beam. The symbol timing recovery controller 132 maycontinuously perform symbol timing recovery on the first reception beambased on a symbol timing offset that is generated using a target SSBreceived in an SSB period before the m-th SSB period. However, as thefirst reception beam is changed to the second reception beam in the m-thSSB period, it may be desirable to determine whether the target SSB,e.g., the j-th SSB SSB_j,m, received via the second reception beam issuitable for a first symbol timing recovery STR1.

Accordingly, the symbol timing recovery controller 132 may determinewhether to perform the first symbol timing recovery STR1 on the secondreception beam using the target SSB, e.g., the j-th SSB SSB_j,m, whenthe first reception beam is changed to the second reception beam toupdate the best reception beam in the m-th SSB period. The symbol timingrecovery controller 132 may generate a reception quality of the targetSSB, e.g., the j-th SSB SSB_j,m, and determine whether to perform thefirst symbol timing recovery STR1 based on the reception quality. Forexample, the symbol timing recovery controller 132 may perform the firstsymbol timing recovery STR1 using the target SSB, e.g., the j-th SSBSSB_j,m, when the reception quality of the target SSB, e.g., the j-thSSB SSB_j,m, is equal to or higher than a reference quality. The symboltiming recovery controller 132 may generate a symbol timing offset usingthe target SSB, e.g., the j-th SSB SSB_j,m, and perform the first symboltiming recovery STR1 based on the symbol timing offset.

The symbol timing recovery controller 132 may perform a second symboltiming recovery STR2 and a third symbol timing recovery STR3 using theneighbor SSBs, e.g., the i-th SSB SSB_i,m and/or the k-th SSB SSB_k,m,when the reception quality of the target SSB, e.g., the j-th SSBSSB_j,m, is lower than the reference quality. In some embodiments, thesymbol timing recovery controller 132 may select one of the i-th SSBSSB_i,m and/or the k-th SSB SSB_k,m and perform a symbol timing recoverycorresponding to the selected neighbor SSB using the selected neighborSSB.

FIGS. 13A and 13B are diagrams for explaining a method of operating asymbol timing recovery controller, according to an example embodiment.FIG. 3 will also be referred to in the description below.

Referring to FIGS. 13A and 13B, a symbol timing offset between atransmission symbol timing timing_TX of a base station and a symboltiming of the wireless communication device 100 may be different foreach SSB. For example, the wireless communication device 100 may receivethe target SSB, e.g., the j-th SSB SSB_j,m−1, and the neighbor SSBs,e.g., the i-th SSB SSB_i,m−1 and the k-th SSB SSB_k,m−1, from a basestation via the best reception beam (e.g., a first reception beam) inthe (m−1)-th SSB period before the m-th SSB period; and a symbol timingoffset Δtiming_SSBj,m−1 generated (or estimated) using the target SSB,e.g., the j-th SSB SSB_j,m−1, may be different from symbol timingoffsets Δtiming_SSBi,m−1 and Δtiming_SSBk,m−1 generated (or estimated)using the neighbor SSBs, e.g., the i-th SSB SSB_i,m−1 and the k-th SSBSSB_k,m−1. For example, an i-th offset difference diff_timing_i may bebetween the symbol timing offset Δtiming_SSBj,m−1 generated (orestimated) using the target SSB, e.g., the j-th SSB SSB_j,m−1, and thesymbol timing offset Δtiming_SSBi,m−1 generated (or estimated) using thei-th SSB SSB_i,m−1; and a k-th offset difference diff_timing_k may bebetween the symbol timing offset Δtiming_SSBj,m−1 generated (orestimated) using the target SSB, e.g., the j-th SSB SSB_j,m−1, and thesymbol timing offset Δtiming_SSBk,m−1 generated (or estimated) using thek-th SSB SSB_k,m−1.

The symbol timing recovery controller 132 may generate the i-th and k-thoffset differences diff_timing_i and diff_timing_k using the symboltiming offsets Δtiming_SSBj,m−1, Δtiming_SSBi,m−1, and Δtiming_SSBk,m−1.

According to an example embodiment, the symbol timing recoverycontroller 132 may generate an offset difference between a symbol timingoffset, which is generated (or estimated) using a target SSB receivedvia the best reception beam in a certain SSB period, and each of symboltiming offsets, which are respectively generated (or estimated) usingneighbor SSBs received via the best reception beam. The symbol timingrecovery controller 132 may reflect the offset differences in a symboltiming recovery using at least one SSB selected from neighbor SSBsafterwards. In detail, the symbol timing recovery controller 132 may usethe i-th and k-th offset differences diff_timing_i and diff_timing_kwhen generating (or estimating) alternate symbol timing offsets usingneighbor SSBs, e.g., the i-th SSB SSB_i,m and the k-th SSB SSB_k,m,received in the m-th SSB period in FIG. 5.

In detail, the symbol timing recovery controller 132 may apply theoffset differences using Equation 4:

$\begin{matrix}{{f_{STR}\left( {\Delta\; t_{Alternate}} \right)}{{{where}\mspace{14mu}\Delta\; t_{Alternate}} = {{\Delta\; t_{{SSB}_{j,{m - 1}}}} + {\frac{1}{\Sigma_{y \in {{Neighbor}\mspace{14mu}{SSBs}}}\mspace{14mu}\sigma_{e{(y)}}^{- 2}}\Sigma_{x \in {{Neighbor}\mspace{14mu}{SSBs}}}\frac{e(x)}{\sigma_{e{(x)}}^{- 2}}}}}{{e(x)} = {{\Delta\; t_{{SSB}_{{- x},m}}} - {\Delta\; t_{{SSB}_{{- x},{m - 1}}}}}}} & (4)\end{matrix}$

Here, when the quality of Δt_(SSB) _(_x,m) −Δt_(SSB) _(_x,m−1) is notknown, a simple arithmetic mean may be calculated using Equation 5:

$\begin{matrix}{{\Delta\; t_{Alternate}} = {{\Delta\; t_{{SSB}_{{- j},{m - 1}}}} + {\frac{1}{{{Neighbor}\mspace{14mu}{SSBs}}}{\sum\limits_{x \in {{Neighbor}\mspace{14mu}{SSBs}}}{e(x)}}}}} & (5)\end{matrix}$

When there are a plurality of neighbor SSBs SSB_x, the symbol timingrecovery controller 132 may generate an alternate symbol timing offsetΔt_(Alternate) by performing a calculation on a symbol timing offsetΔt_(SSB_j,m−1) corresponding to the target SSB, e.g., the j-th SSBSSB_j,m−1, and a symbol timing offset Δt_(SSB_x,m-1) corresponding to aneighbor SSB, e.g., the x-th SSB SSB_x,m−1, in the (m−1)-th SSB period(or a random SSB period) and a symbol timing offset Δt_(SSB_x,m)corresponding to a neighbor SSB, e.g., the x-th SSB SSB_x,m, in the m-thSSB period, based on Equation 4 or 5. The symbol timing recoverycontroller 132 may perform a symbol timing recovery based on anapplication result (e.g., the alternate symbol timing offsetΔt_(Alternate)).

FIG. 14 is a block diagram of an electronic apparatus 1000 according toan example embodiment.

Referring to FIG. 14, the electronic apparatus 1000 may include a memory1010, a processor unit 1020, an input/output controller 1040, a displayunit 1050, an input device 1060, and/or a communication processor 1090.Here, there may be a plurality of memories 1010. Each element will bedescribed below.

The memory 1010 may include a program storage 1011, which may store aprogram for controlling operations of the electronic apparatus 1000,and/or a data storage 1012, which may store data generated duringexecution of the program. The data storage 1012 may store data used forexecution of an application program 1013 and/or an automatic frequencycontrol (AFC)/symbol timing recovery (STR) program 1014. The programstorage 1011 may include the application program 1013 and/or the AFC/STRprogram 1014. Here, a program included in the program storage 1011 maybe a set of instructions and expressed as an instruction set.

The application program 1013 may include an application programoperating in the electronic apparatus 1000. In other words, theapplication program 1013 may include instructions of an application runby processing circuitry (e.g., a processor 1022). When the bestreception beam is changed to another reception beam as a result ofupdating the best reception beam, according to embodiments, the AFC/STRprogram 1014 may select one of a target SSB and/or at least one neighborSSB, which are received in an SSB period corresponding to the time ofbeam changing, and perform an automatic frequency control and/or asymbol timing recovery on the changed reception beam using the selectedSSB.

A peripheral device interface 1023 may control connection among aninput/output peripheral device of a base station, the processor 1022,and a memory interface 1021. The processor 1022 may control a basestation to provide a service using at least one software program. Atthis time, the processor 1022 may execute at least one program stored inthe memory 1010 such that a service corresponding to the program may beprovided.

The input/output controller 1040 may provide an interface between aninput/output device, such as the display unit 1050 and/or the inputdevice 1060, and the peripheral device interface 1023. The display unit1050 may display status information, input text, a moving picture,and/or a still picture. For example, the display unit 1050 may displayinformation on an application program run by the processor 1022.

The input device 1060 may provide input data, which may be generated bythe selection of the electronic apparatus 1000, to the processor unit1020 through the input/output controller 1040. The input device 1060 mayinclude a keypad, which includes at least one hardware button, and/or atouch pad sensing touch information. For example, the input device 1060may provide touch information, such as a touch, a movement of the touch,and/or the release of the touch, detected through a touch pad to theprocessor 1022 through the input/output controller 1040. The electronicapparatus 1000 may include the communication processor 1090 that mayperform communication functions for voice communication and datacommunication. The communication processor 1090 may include at least onephased array. The AFC/STR program 1014 may control the communicationprocessor 1090 when the best reception beam is updated according toembodiments.

Conventional devices for performing beamforming in 5G communicationsystems skip performance of automatic frequency control and/or symboltiming recovery when the reception quality of a target SSB is notsatisfactory while a reception beam is being changed. By skippingperformance of automatic frequency control and/or symbol timing recoveryin such situations, the conventional devices degrade the communicationperformance between the conventional devices within the 5G communicationsystems.

However, some example embodiments describe a wireless communicationdevice 100 that may perform automatic frequency control and/or symboltiming recovery using a neighbor SSB, instead of skipping theperformance of automatic frequency control and/or symbol timingrecovery, when the reception quality of the target SSB is notsatisfactory. Accordingly, the wireless communication device 100overcomes the above-mentioned deficiencies of the conventional devicesto prevent or reduce degradation of communication performance.

While the inventive concepts have been particularly shown and describedwith reference to embodiments thereof, it will be understood thatvarious changes in form and details may be made therein withoutdeparting from the spirit and scope of the following claims.

What is claimed is:
 1. A method of operating a wireless communicationdevice for correcting an offset between a base station and the wirelesscommunication device, the method comprising: determining whether toperform offset correction using a first target synchronization signalblock (SSB) to generate a determination result in response to changing aselected reception beam from a first reception beam to a secondreception beam in an SSB period, the first target SSB being received viathe second reception beam; and performing the offset correction on thesecond reception beam based on the determination result by generating anoffset using at least one first neighbor SSB, the at least one firstneighbor SSB being received via the first reception beam.
 2. The methodof claim 1, wherein the performing the offset correction includes atleast one of an automatic frequency control or a symbol timing recovery.3. The method of claim 1, wherein the first reception beam is initiallyselected as the selected reception beam for wireless communicationbetween the base station and the wireless communication device as afirst result of beam sweeping; and the first target SSB corresponds to aselected transmission beam of the base station, the selectedtransmission beam being determined to be paired with the first receptionbeam as a second result of the beam sweeping.
 4. The method of claim 3,wherein the changing changes the selected reception beam to the secondreception beam according to a variable communication environment of thewireless communication device.
 5. The method of claim 1, furthercomprising: receiving a plurality of SSBs via the first reception beamin the SSB period, the plurality of SSBs not including the first targetSSB; determining a reception quality of each of the plurality of SSBs;and determining at least one SSB among the plurality of SSBs having thereception quality equal to or higher than a reference quality as the atleast one first neighbor SSB.
 6. The method of claim 5, wherein thereception quality of each of the plurality of SSBs includes at least oneof a reference signal received power (RSRP) or a signal-to-noise ratio(SNR).
 7. The method of claim 1, wherein the determining whether toperform the offset correction using the first target SSB includes:determining a reception quality of the first target SSB; and determiningto perform the offset correction using the at least one first neighborSSB in response to the reception quality being lower than a referencequality.
 8. The method of claim 7, wherein the reference quality is setbased on a reception quality of the at least one first neighbor SSBreceived in the SSB period and a reception quality of a second targetSSB received in at least one other SSB period.
 9. The method of claim 1,wherein the offset is a first offset, the first offset including atleast one of an alternate frequency offset or an alternate symbol timingoffset; and the performing the offset correction performs the offsetcorrection based on the first offset.
 10. The method of claim 9, whereinthe generating the offset comprises: generating a second offset usingthe at least one first neighbor SSB; and generating the first offset byapplying an offset difference to the second offset, the offsetdifference being between a second target SSB and at least one secondneighbor SSB, the second target SSB and the at least one second neighborSSB being received via the first reception beam in at least one otherSSB period.
 11. The method of claim 1, wherein the performing the offsetcorrection comprises: generating a reception quality of the at least onefirst neighbor SSB; and performing the offset correction using the atleast one first neighbor SSB in the SSB period in response to thereception quality being equal to or higher than a reference quality. 12.The method of claim 1, wherein the performing the offset correction onthe second reception beam continuously performs the offset correction onthe second reception beam; and the performing the offset correction onthe second reception beam performs the offset correction on the secondreception beam after offset correction has been performed on the firstreception beam and in response to the changing.
 13. The method of claim1, wherein the changing changes the selected reception beam from thefirst reception beam to the second reception beam based on the secondreception beam being in tune with a transmission beam.